You know how it happens — your seven-year-old is hungry and wants a bag of chips or a cookie while you are out. Your son drinks all of your large soda as you chat with a friend. It is not easy to monitor, let alone restrict, the calories your child takes in. But it is beginning to look like parents who are careless in this way may be endangering their children.
The epidemic of childhood overweight and obesity is well documented and the medical and popular literature abound with dire predictions about future health problems including heart disease, diabetes, and others. But parents need to know that being overweight poses serious risks to children's physical and emotional health, as well as limiting their ability to function physically and socially — not just down the road in adulthood, but right now, in childhood, according to a new study.
Using data from the 2007 National Survey of Children’s Health (NSCH) researchers were able to gather information about the physical and mental health and social functioning of 43,297 children, ages 10 through 17 from phone interviews with parents. Parents were also asked their child’s height and weight. With this information, researchers were able to calculate each child's body mass index (BMI) and compare it to those of other children of the same age, height and sex.
A six-year-old girl who is 3 feet, 7 inches tall and weighs 48 pounds would be in the 91st percentile and considered overweight.
Kids whose height and weight put their BMIs in the 85th to 95th percentiles compared with children of the same age and sex were considered overweight. For example, a six-year-old girl who is 3 feet 7 inches tall and weighs 48 pounds would be in the 91st percentile and considered overweight. Those with a BMI above the 95th percentile based on growth charts from the Centers for Disease Control and Prevention) were designated as obese.
The children's general health, any physical or limitations in activity they might have, as well as behavior problems, mood problems, and how they were doing at school were all explored, as were specific health conditions including diabetes, dental health, bone, joint or muscle problems, asthma, allergies, headaches, and even ear infections. Parents were also asked about mental and developmental issues such as ADHD, conduct disorder, depression, anxiety, learning disability and developmental delay.
Among all the children, 15% met criteria for overweight and 16% were obese. Obesity rates were almost three times higher for children in poor families, and nearly two times higher for black and Hispanic children as compared with white, non-Hispanic children. There were also higher obesity rates found in single-mother families and in households with lower education.
Obese and overweight children both had more physical health problems, poorer emotional functioning, and increased school problems than their normal weight peers.
When two disorders or illnesses occur in the same person, simultaneously or one after another, they are called comorbid. Obese children were found to have higher rates of comorbidity with health problems including ADHD, learning disabilities, asthma, allergies and headaches. According to the researchers, “Overall, obese children had nearly twice the risk of having three or more reported mental health, developmental, or physical health conditions, while overweight children had 1.3 times higher risk. This remained true even when socio-demographic factors were taken into consideration. In addition, the more overweight the children were, the higher numbers of additional health and psychosocial problems they showed.”
In other cases it is possible that the health, behavior, or school problem may be the cause of the overweight and obesity.
There are several possible explanations as to why the heavier children had more health and behavioral problems, according to the authors, all at the University of California, Los Angeles. In some situations, being overweight or obese may directly cause disease. For example, it is known that excessive weight causes diabetes and overweight children are being diagnosed with type 2 diabetes earlier and with increasing frequency. In other cases it is possible that the health, behavior, or school problem may be the cause of the overweight and obesity. This might occur when a normal weight person becomes depressed, overeats and is physically inactive leading to excessive weight gain. A third possibility is that the overweight/obesity and the comorbid condition might both stem from the same abnormality. For example, it is known that neurotransmitters affect impulse control and appetite. Perhaps an abnormality of a brain chemical leads to attention problems, and poor eating habits manifesting as both ADHD and overweight.
A commentary on this study explores the significant effect of stress on the body’s neuroendocrine balance. When the individual is stressed, and more cortisol is produced, overweight and obesity may be the result. Thus, living with chronic psychosocial stress from poor school performance, perhaps as the result of an attention problem, can lead to overweight. But teasing cause and effect apart can be difficult: overweight and obesity are in themselves stressful life conditions and can perpetuate this vicious cycle by inducing the release of more stress hormones potentially leading to more weight gain.
Our current environment of constant food cues, immediate gratification, and sensory overload may serve to intensify the effects of these biological predispositions on excessive weight gain.
The commentary also notes that the clustering of obesity with school functioning difficulties supports the possibility that there is a common pathway for both. They note that studies have shown a role for the neurochemical, dopamine, in both ADHD and overweight. An abnormality of a single chemical may cause a constellation of health and behavioral problems.
Genetic predispositions and environmental influences may interact to promote obesity across generations. According to the commentary author, Julie C. Lumeng, “This neurobiology may be shared within families, contributing to parenting behaviors that are obesity promoting; for example, if a mother also has ADHD-like behaviors and great reward sensitivity to food, she may find restricting access to highly palatable foods in the home particularly challenging. Our current environment of constant food cues, immediate gratification, and sensory overload may serve to intensify the effects of these biological predispositions on excessive weight gain.”
Learning disabilities and obesity may also be linked in more than one way. The bullying and victimization that overweight students experience in school could lead to emotional difficulties and poor school function as children have a difficult time concentrating on their academic pursuits when they are emotionally stressed. Additionally, it is known that fat tissue releases inflammatory compounds that cause a low-grade level of inflammation in overweight/obese people. Such inflammation can cause mood disorders as well as impair thinking and reasoning skills leading to poor school performance.
The interconnections between overweight/obesity and physical, emotional, and cognitive health are diverse and complex. No single model will cover all situations. This study clearly shows that long before children experience the organ-system damage that comes with chronic overweight, they are experiencing mental, behavioral and physical health effects while they are still school age. These effects have both immediate and long lasting impact that inhibits the development of their full potential.